SAT English Practice Question

The scientists who discovered the new species of bacteria, which were found in a remote cave system, were from several countries—the United States, Japan, and Brazil. They spent years collecting samples in the harsh environment, facing extreme temperatures and navigating dangerous terrain. Their research has led to the creation of a new antibiotic, which has shown promise in treating resistant strains of bacteria.

1. A.which were found in a remote cave system,
2. B.that were found in a remote cave system,
3. C.which were found in a remote cave system;
4. D.which were found in a remote cave system—